Printer UPC - E1 in Java LOOKUP

Using Barcode reader for Java Control to read, scan read, scan image in Java applications.

OnBarcode.com/UCC - 12

Figure 6-3 shows the example implemented in the following paragraphs. Both windows are in a separate module, each independent of the other (i.e., both can be exchanged or new ones can be added arbitrarily).

Using Barcode creation for Java Control to generate, create Linear image in Java applications.

OnBarcode.com/Linear

Figure 6-3. Typical application example of a data exchange between two modules, without interdependency The structure of this concept is shown in Figure 6-4. The class Mp3SearchList in module A represents a list of search results. A search result entry is represented by the class Mp3FileObject, residing in a separate module, since this class is the most common denominator of all modules. If an entry is selected in the list, the Mp3FileObject instance is added to the local Lookup. A moderator (i.e., a proxy component depicted as the interface ContextGlobalProvider) is needed to decouple modules A and B. This proxy component provides the local Lookup of module A to module B, which contains the currently selected instance. To enable the centralized proxy component to access the local Lookup of the class Mp3SearchList, the Lookup API provides the interface Lookup.Provider. This interface must be implemented from the class Mp3SearchList. Using the method getLookup(), the local Lookup can be obtained. The Lookup.Provider interface is already implemented by the class TopComponent, which is the superclass of all visible NetBeans window system components, as well as the Mp3SearchList. The NetBeans window system already provides an instance of the central proxy component, the class GlobalActionContextImpl. This class provides a proxy Lookup, which accesses the local Lookup of the focused TopComponent. This Lookup can be obtained by calling the static utility method Utilities. actionsGlobalContext(). So, there is no need to create our own ContextGlobalProvider instance, but we already have access to the global proxy Lookup. If you are interested

Using Barcode printer for Android Control to generate, create UPC - E1 image in Android applications.

OnBarcode.com/GTIN - 12

Figure 6-4. Structure of the intermodule communication concept using a local Lookup via a proxy component to decouple subject and observer The class Mp3DetailsView gains access to the local Lookup of the Mp3SearchList by calling Utilities.actionsGlobalContext(). Based on the global Proxy Lookup, we create a Lookup. Result for the class Mp3FileObject. An instance of the class Lookup.Result provides a subset of a Lookup for a special class. The main advantage is that the user can listen for changes in this subset by using a LookupListener. So, the component will be notified as soon as another Mp3FileObject is selected in the Mp3SearchList, or if the window showing the Mp3SearchList loses focus. As an example, no detailed MP3 information will be displayed.

Using Barcode generation for Office Word Control to generate, create QR image in Office Word applications.

OnBarcode.com/QR Code ISO/IEC18004

Following, you find the classes of this example application. Only the important parts of the classes are shown. First, we have the class Mp3SearchList, which represents a window, and because of this, extends from the base class TopComponent. To enable listening to selection changes in the result list, we also implement the ListSelectionListener interface. As a private member, we have a data model that manages the data in the table. For demonstration purposes, a simple data model has been chosen, creating three example objects of the class Mp3FileObject in the constructor and adding them to the model. This data would normally be provided using the search algorithm. The second private member object is an instance of InstanceContent. This enables us to dynamically change the content of the Lookup. In the constructor of the Mp3SearchList, we can now create a local Lookup, using the class AbstractLookup and passing our InstanceContent object into its constructor. Using the method associateLookup(), our local Lookup is set as the Lookup of the TopComponent, so that it will be returned from the getLookup() method. In the method valueChanged(), which gets called if a data set is selected in the table, we get the data set from the data model, wrap it into a collection, and pass it to our InstanceContent instance (see Listing 6-6), which is the data storage for the Lookup. So, the selected element is always part of the local Lookup. Listing 6-6. Mp3SearchList displays the search results in a table and adds the actual selected data set to the local Lookup. public class Mp3SearchList extends TopComponent implements ListSelectionListener { private Mp3SearchListModel model = new Mp3SearchListModel(); private InstanceContent content = new InstanceContent(); private Mp3SearchList() { initComponents(); searchResults.setModel(model); searchResults.getSelectionModel().addListSelectionListener(this); associateLookup(new AbstractLookup(content)); } public void valueChanged(ListSelectionEvent event) { if(!event.getValueIsAdjusting()) { Mp3FileObject mp3 = model.getRow(searchResults.getSelectedRow()); content.set(Collections.singleton(mp3), null); } } } Here, the data model Mp3SearchListModel of the table with the search results is just an example and is kept quite simple (see Listing 6-7). Three objects of the type Mp3FileObject are directly created in the constructor. Listing 6-7. Simplified data model managing and providing the data for the result list public class Mp3SearchListModel extends AbstractTableModel { private String[] columns = {"Artist", "Title", "Year"}; private Vector<Mp3FileObject> data = new Vector<Mp3FileObject>(); public Mp3SearchListModel() { data.add(new Mp3FileObject("Gigi D'Agostino", "The rain", "2006"));